1. Field of the Invention
This invention relates to a control system for a stepping motor.
2. Description of the Prior Art
When a stepping motor shifts from its moving state to its stopped state, the mover of the stepping motor usually effects attenuation vibration near the objective stable point and becomes stationary. In order to shorten the time until the mover stops via this attenuation vibration, there has heretofore been proposed a system in which the kinetic energy of the mover when it has reached the stable point is brought close to 0 by manipulating the excitation phase or the excitation time and thereby the vibration is quickly brought to a close.
Such a conventional system, however, can hardly obtain the desired result when the load applied to the motor fluctuates and in addition, the mode in which the vibration comes to an end differs greatly each time depending on the irregularity of the torque of the motor itself, and this has led to a problem that where the motor is actually used, the time until the vibration comes to an end (the damping time) must unavoidably be set with a sufficient allowance.
So, where high-speed operation of the motor is required, it has been unavoidable in the conventional system to provide a position detector or the like and construct a close loop control system using the detection output thereof, and this in turn has led to the bulkiness and expensiveness of the control system including the stepping motor.